Dataset Information

Mitochondrial genomes reveal recombination in the presumed asexual Fusarium oxysporum species complex.

ABSTRACT: The Fusarium oxysporum species complex (FOSC) contains several phylogenetic lineages. Phylogenetic studies identified two to three major clades within the FOSC. The mitochondrial sequences are highly informative phylogenetic markers, but have been mostly neglected due to technical difficulties.A total of 61 complete mitogenomes of FOSC strains were de novo assembled and annotated. Length variations and intron patterns support the separation of three phylogenetic species. The variable region of the mitogenome that is typical for the genus Fusarium shows two new variants in the FOSC. The variant typical for Fusarium is found in members of all three clades, while variant 2 is found in clades 2 and 3 and variant 3 only in clade 2. The extended set of loci analyzed using a new implementation of the genealogical concordance species recognition method support the identification of three phylogenetic species within the FOSC. Comparative analysis of the mitogenomes in the FOSC revealed ongoing mitochondrial recombination within, but not between phylogenetic species.The recombination indicates the presence of a parasexual cycle in F. oxysporum. The obstacles hindering the usage of the mitogenomes are resolved by using next generation sequencing and selective genome assemblers, such as GRAbB. Complete mitogenome sequences offer a stable basis and reference point for phylogenetic and population genetic studies.

SUBMITTER: Brankovics B

PROVIDER: S-EPMC5604515 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Mitochondrial genomes reveal recombination in the presumed asexual Fusarium oxysporum species complex.

Brankovics Balázs B van Dam Peter P Rep Martijn M de Hoog G Sybren GS J van der Lee Theo A TA Waalwijk Cees C van Diepeningen Anne D AD

BMC genomics 20170918 1

<h4>Background</h4>The Fusarium oxysporum species complex (FOSC) contains several phylogenetic lineages. Phylogenetic studies identified two to three major clades within the FOSC. The mitochondrial sequences are highly informative phylogenetic markers, but have been mostly neglected due to technical difficulties.<h4>Results</h4>A total of 61 complete mitogenomes of FOSC strains were de novo assembled and annotated. Length variations and intron patterns support the separation of three phylogeneti ...[more]

PMID: 28923029

Similar Datasets

Project description:BackgroundThe availability of mitochondrial genomes has allowed for the resolution of numerous questions regarding the evolutionary history of fungi and other eukaryotes. In the Gibberella fujikuroi species complex, the exact relationships among the so-called "African", "Asian" and "American" Clades remain largely unresolved, irrespective of the markers employed. In this study, we considered the feasibility of using mitochondrial genes to infer the phylogenetic relationships among Fusarium species in this complex. The mitochondrial genomes of representatives of the three Clades (Fusarium circinatum, F. verticillioides and F. fujikuroi) were characterized and we determined whether or not the mitochondrial genomes of these fungi have value in resolving the higher level evolutionary relationships in the complex.ResultsOverall, the mitochondrial genomes of the three species displayed a high degree of synteny, with all the genes (protein coding genes, unique ORFs, ribosomal RNA and tRNA genes) in identical order and orientation, as well as introns that share similar positions within genes. The intergenic regions and introns generally contributed significantly to the size differences and diversity observed among these genomes. Phylogenetic analysis of the concatenated protein-coding dataset separated members of the Gibberella fujikuroi complex from other Fusarium species and suggested that F. fujikuroi ("Asian" Clade) is basal in the complex. However, individual mitochondrial gene trees were largely incongruent with one another and with the concatenated gene tree, because six distinct phylogenetic trees were recovered from the various single gene datasets.ConclusionThe mitochondrial genomes of Fusarium species in the Gibberella fujikuroi complex are remarkably similar to those of the previously characterized Fusarium species and Sordariomycetes. Despite apparently representing a single replicative unit, all of the genes encoded on the mitochondrial genomes of these fungi do not share the same evolutionary history. This incongruence could be due to biased selection on some genes or recombination among mitochondrial genomes. The results thus suggest that the use of individual mitochondrial genes for phylogenetic inference could mask the true relationships between species in this complex.

Project description:The Fusarium oxysporum species complex (FOSC) is a group of soilborne pathogens causing severe disease in more than 100 plant hosts, while individual strains exhibit strong host specificity. Both chromosome transfer and comparative genomics experiments have demonstrated that lineage-specific (LS) chromosomes contribute to the host-specific pathogenicity. However, little is known about the functional importance of genes encoded in these LS chromosomes. Focusing on signaling transduction, this study compared the kinomes of 12 F. oxysporum isolates, including both plant and human pathogens and 1 nonpathogenic biocontrol strain, with 7 additional publicly available ascomycete genomes. Overall, F. oxysporum kinomes are the largest, facilitated in part by the acquisitions of the LS chromosomes. The comparative study identified 99 kinases that are present in almost all examined fungal genomes, forming the core signaling network of ascomycete fungi. Compared to the conserved ascomycete kinome, the expansion of the F. oxysporum kinome occurs in several kinase families such as histidine kinases that are involved in environmental signal sensing and target of rapamycin (TOR) kinase that mediates cellular responses. Comparative kinome analysis suggests a convergent evolution that shapes individual F. oxysporum isolates with an enhanced and unique capacity for environmental perception and associated downstream responses.IMPORTANCE Isolates of Fusarium oxysporum are adapted to survive a wide range of host and nonhost conditions. In addition, F. oxysporum was recently recognized as the top emerging opportunistic fungal pathogen infecting immunocompromised humans. The sensory and response networks of these fungi undoubtedly play a fundamental role in establishing the adaptability of this group. We have examined the kinomes of 12 F. oxysporum isolates and highlighted kinase families that distinguish F. oxysporum from other fungi, as well as different isolates from one another. The amplification of kinases involved in environmental signal relay and regulating downstream cellular responses clearly sets Fusarium apart from other Ascomycetes Although the functions of many of these kinases are still unclear, their specific proliferation highlights them as a result of the evolutionary forces that have shaped this species complex and clearly marks them as targets for exploitation in order to combat disease.

Project description:Chinese yam (Dioscorea polystachya Thunb.) is an important root crop. Wilt caused by Fusarium is among the most important emerging diseases on yams. However, there is currently limited information on the molecular epidemiology of Fusarium causing yam wilt. Here, we investigated wilted yam samples from six regions in South-Central China. A total of 117 Fusarium isolates were obtained from diseased tissues of 37 wilted yam plants. These yam plants belonged to two varieties characterized by white and purple fleshy tubers, respectively. Analyses of ef1-α sequences identified that these 117 Fusarium isolates belonged to 11 putative species, with F. aff. commune being the most common (31.6%), followed by F. aff. cugenangense (29.1%), a potential undescribed species Fusarium aff. sp. (11.1%), F. aff. gossypinum (9.4%), F. aff. fujikuroi (8.5%), F. aff. nirenbergiae (6%), and one isolate each (0.85%) of F. aff. asiaticum, F. aff. curvatum, F. aff. odoratissimum, F. aff. solani, and F. aff. verticillioides. Six of these species were recently described as new species within the Fusarium oxysporum species complex (FOSC). Interestingly, 18 of the 37 yam plants were infected by two or more Fusarium species each and there was evidence for differential Fusarium species distributions based on geographic location and/or yam host variety. Multilocus microsatellite genotyping of the 67 FOSC isolates revealed that isolates of the same species from the same diseased plants often belonged to different genotypes. Interestingly, several FOSC microsatellite genotypes were shared among distinct geographic regions, consistent with long-distance dispersal. However, population genetic analyses revealed significant contributions of geographic separation to the overall genetic variation of FOSC with several pairs of geographic populations showing significant genetic differentiations, consistent with differential geographic distribution of the species within FOSC. The implications of our results to the managements of Fusarium wilt in yams were discussed.

Dataset Information

Mitochondrial genomes reveal recombination in the presumed asexual Fusarium oxysporum species complex.

Publications

Mitochondrial genomes reveal recombination in the presumed asexual Fusarium oxysporum species complex.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets